Anti-inflammatory effects of N-acylethanolamines in rheumatoid arthritis synovial cells are mediated by TRPV1 and TRPA1 in a COX-2 dependent manner.

Lowin T, Apitz M, Anders S, Straub RH - Arthritis Res. Ther. (2015)

Bottom Line:
The effects of OEA and PEA on SFs were diminished by FAAH inhibition.N-acylethanolamines exert anti-inflammatory effects in SFs.A dual FAAH/COX-2 inhibitor, increasing N-acylethanolamine levels with concomitant TRP channel desensitization, might be a good candidate to inhibit the production of proinflammatory mediators of synovial cells and to reduce erosions.

Introduction: The endocannabinoid system modulates function of immune cells and mesenchymal cells such as fibroblasts, which contribute to cartilage destruction in rheumatoid arthritis (RA). The aim of the study was to determine the influence of N-acylethanolamines anandamide (AEA), palmitoylethanolamine (PEA) and oleylethanolamine (OEA) on several features of arthritic inflammation in vitro (human material) and in vivo (a mouse model).

Methods: Immunofluorescence and western blotting were used to detect cannabinoid receptors and related enzymes. Cytokines and MMP-3 were measured by ELISA. Intracellular signaling proteins were detected by proteome profiling. Proliferation was quantified by CTB reagent. Adhesion was assessed by the xCELLigence system. After onset of collagen type II arthritis, mice were treated daily with the FAAH inhibitor JNJ1661010 (20 mg/kg) or vehicle.

Results: IL-6, IL-8 and MMP-3 (determined only in synovial fibroblasts (SFs)) were downregulated in primary synoviocytes and SFs of RA and OA after AEA, PEA and OEA treatment. In SFs, this was due to activation of TRPV1 and TRPA1 in a COX-2-dependent fashion. FAAH inhibition increased the efficacy of AEA in primary synoviocytes but not in SFs. The effects of OEA and PEA on SFs were diminished by FAAH inhibition. Adhesion to fibronectin was increased in a CB1-dependent manner by AEA in OASFs. Furthermore, elevation of endocannabinoids ameliorated collagen-induced arthritis in mice.

Conclusions: N-acylethanolamines exert anti-inflammatory effects in SFs. A dual FAAH/COX-2 inhibitor, increasing N-acylethanolamine levels with concomitant TRP channel desensitization, might be a good candidate to inhibit the production of proinflammatory mediators of synovial cells and to reduce erosions.

Mentions:
The AEA congeners OEA and PEA are also activators/desensitizers at TRPV1 channels and we therefore tested whether cation channels might be general targets of N-acylethanolamines in SF. While OEA (10−11 M to 10−6 M) by itself did not modulate IL-6, IL-8 and MMP-3 production (Fig. 4a, c, e, black curves), combination with the COX-2 inhibitor nimesulide significantly reduced cytokine and MMP-3 production (Fig. 4a, c, e, red curves). A combination of OEA and the FAAH inhibitor JNJ1661010 (100nM) had no effect on IL-6, IL-8 and MMP-3 secretion by RASF (data not shown). Similar to its effects in combination with AEA, the TRPA1 antagonist A967079 (1 μM) blocked the effects of nimesulide/OEA on TNF-induced IL-8 production (Fig. 4e, blue curve). In addition, the TRPV1 anatgonist capsazepine (1 μM) together with nimesulide/OEA also modulated IL-8 production by RASF (Fig. 4d).Fig. 4

Mentions:
The AEA congeners OEA and PEA are also activators/desensitizers at TRPV1 channels and we therefore tested whether cation channels might be general targets of N-acylethanolamines in SF. While OEA (10−11 M to 10−6 M) by itself did not modulate IL-6, IL-8 and MMP-3 production (Fig. 4a, c, e, black curves), combination with the COX-2 inhibitor nimesulide significantly reduced cytokine and MMP-3 production (Fig. 4a, c, e, red curves). A combination of OEA and the FAAH inhibitor JNJ1661010 (100nM) had no effect on IL-6, IL-8 and MMP-3 secretion by RASF (data not shown). Similar to its effects in combination with AEA, the TRPA1 antagonist A967079 (1 μM) blocked the effects of nimesulide/OEA on TNF-induced IL-8 production (Fig. 4e, blue curve). In addition, the TRPV1 anatgonist capsazepine (1 μM) together with nimesulide/OEA also modulated IL-8 production by RASF (Fig. 4d).Fig. 4

Bottom Line:
The effects of OEA and PEA on SFs were diminished by FAAH inhibition.N-acylethanolamines exert anti-inflammatory effects in SFs.A dual FAAH/COX-2 inhibitor, increasing N-acylethanolamine levels with concomitant TRP channel desensitization, might be a good candidate to inhibit the production of proinflammatory mediators of synovial cells and to reduce erosions.

Introduction: The endocannabinoid system modulates function of immune cells and mesenchymal cells such as fibroblasts, which contribute to cartilage destruction in rheumatoid arthritis (RA). The aim of the study was to determine the influence of N-acylethanolamines anandamide (AEA), palmitoylethanolamine (PEA) and oleylethanolamine (OEA) on several features of arthritic inflammation in vitro (human material) and in vivo (a mouse model).

Methods: Immunofluorescence and western blotting were used to detect cannabinoid receptors and related enzymes. Cytokines and MMP-3 were measured by ELISA. Intracellular signaling proteins were detected by proteome profiling. Proliferation was quantified by CTB reagent. Adhesion was assessed by the xCELLigence system. After onset of collagen type II arthritis, mice were treated daily with the FAAH inhibitor JNJ1661010 (20 mg/kg) or vehicle.

Results: IL-6, IL-8 and MMP-3 (determined only in synovial fibroblasts (SFs)) were downregulated in primary synoviocytes and SFs of RA and OA after AEA, PEA and OEA treatment. In SFs, this was due to activation of TRPV1 and TRPA1 in a COX-2-dependent fashion. FAAH inhibition increased the efficacy of AEA in primary synoviocytes but not in SFs. The effects of OEA and PEA on SFs were diminished by FAAH inhibition. Adhesion to fibronectin was increased in a CB1-dependent manner by AEA in OASFs. Furthermore, elevation of endocannabinoids ameliorated collagen-induced arthritis in mice.

Conclusions: N-acylethanolamines exert anti-inflammatory effects in SFs. A dual FAAH/COX-2 inhibitor, increasing N-acylethanolamine levels with concomitant TRP channel desensitization, might be a good candidate to inhibit the production of proinflammatory mediators of synovial cells and to reduce erosions.